Human adenovirus (Ads) have an early region 3 (E3) transcription unit, which codes for proteins that control a variety of innate and acquired host immune responses against virus-infected cells. These proteins, can (1) inhibit apoptosis induced by tumor necrosis factor alpha (TNFalpha), Fas and TRIAL; (2) inhibit the presentation of the class I major histocompatibility complex (MHC) at the cell surface and (3) inhibit the production of chemokines induced by TNFalpha. Our original hypotheses that these gene products could be used to facilitate allogeneic pancreatic beta-cell transplantation and prevent autoimmune diabetes have been proven in several mouse models including the nonobese diabetic mouse (NOD), streptozotocin-induced diabetes and the lymphocytic choriomeningitis virus (LCMV)-induced model of diabetes. Previous experiments have been performed primarily in transgenic mice carrying the entire Ad2 E3 transcription region behind the rat insulin promoter (RIP) to test these hypotheses. More recently, the Ad E3 genes also have been inserted into conditionally-immortalized, growth-controlled murine beta-cell lines, which correct diabetes even after allogeneic transplantation. Future studies will address the mechanism of E3 protection of mouse islets challenged by the autoimmune and allogeneic rejection processes, while attempting to extend the beneficial immunoprotective effects to human islets or human fetal hepatocyte precursors (see Project 4) differentiated to produce insulin. We propose to 1) treat diabetes in NOD mice by transplantation of an allogeneic murine beta-cell line, containing the Ad E3 immunoregulatory transgenes to prevent rejection and tracycline-regulated SV40 Tag to control growth. 2) Study the inhibition of both chemokine synthesis and NF-kappaB dependent transcription by Ad E3 genes in beta-cell lines in cultures exposed to cytokines (TNFalpha, IL-1beta) and 3) develop xenograft models to study the function of Ad E3 genes in preventing rejection of human (a) islets or (b) insulin-producing hepatocyte precursor cells. Islets and hepatocytes will be challenged by human immune effector cells such as peripheral blood mononuclear cells (PBMC's) in NOD/SCID/beta2-minus mice.